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HUG - here for all audio enthusiasts

Since its inception ten years ago, the Harbeth User Group's ambition has been to create a lasting knowledge archive. Knowledge is based on facts and observations. Knowledge is timeless. Knowledge is human independent and replicatable. However, we live in new world where thanks to social media, 'facts' have become flexible and personal. HUG operates in that real world.

HUG has two approaches to contributor's Posts. If you have, like us, a scientific mind and are curious about how the ear works, how it can lead us to make the right - and wrong - decisions, and about the technical ins and outs of audio equipment, how it's designed and what choices the designer makes, then the factual area of HUG is for you. The objective methods of comparing audio equipment under controlled conditions has been thoroughly examined here on HUG and elsewhere and can be easily understood and tried with negligible technical knowledge.

Alternatively, if you just like chatting about audio and subjectivity rules for you, then the Subjective Soundings sub-forum is you. If upon examination we think that Posts are better suited to one sub-forum than than the other, they will be redirected during Moderation, which is applied throughout the site.

Questions and Posts about, for example, 'does amplifier A sounds better than amplifier B' or 'which speaker stands or cables are best' are suitable for the Subjective Soundings area.

The Moderators' decision is final in all matters regarding what appears here. That said, very few Posts are rejected. HUG Moderation individually spell and layout checks Posts for clarity but due to the workload, Posts in the Subjective Soundings area, from Oct. 2016 will not be. We regret that but we are unable to accept Posts that present what we consider to be free advertising for products that Harbeth does not make.

That's it! Enjoy!

{Updated Nov. 2016A}
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Working with the human ear: the proper evaluation of audio equipment incl. amplifiers

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  • #16
    its simple....nothing to be bemused about....

    Originally posted by Maccar View Post
    Hi,

    Must admit I'm a bit bemused by this forum..
    Hi maccar

    There’ll be sound differences, im sure, between electronics but the quantum is the one most can’t agree on, or even perceive, to make an objective cost benefit assessment. I think the issue is made more complex by some electronics giving off a flavour, however subtle, of its own. It reminds me of pimply school boys arguing vital statistics of the page 3 model. Its at best pretty academic!

    Would you actually use a comet or target cd player if you could afford say a 20 kg behemoth such as a Teac? The Sony PS3 makes a great CD player but it is rough as a camels back when its spinning ie. its noisy and vibrates.

    So, imo, it all really comes back to what we can afford and whether we like the look and how it sits in your setup. Do you like the philosophy of the company selling you its cd player/ amp? It all sounds rather shallow but if I had a mint ill buy an Esoteric CD player. Why care who thinks what? Ill then get a Bryston monoblock even if the SHL5 doesn’t need 1/10th of the current. If that is not responsible spending, where do we draw the line then. Only we can make that decision.

    What im trying to say at the end of the day is it doesn’t pay to ask for a cd and amp opinion.  cause they really do sound the “same”.  same same as they say in Thailand.

    Comment


    • #17
      Alterntative truths?

      Originally posted by Maccar View Post
      I previously posted about a suitable CDP to go with my set up and promptly blinded with scientific facts...
      What would you prefer to facts?

      Comment


      • #18
        Differences are relatively (very) small between electronics: Buy Wisely!

        I think we should tread a sensible approach. The differences between amps, CD players, stands, cables etc are relatively small, sometimes miniscule when compared to the gross differences between speakers. Sometimes, you sit and struggle to discern the differences between cables but swop speakers and it can be wham, bang - huge changes. I believe that is what the Forum is trying to explain.

        Earlier this week, I spent a few hours with a customer, auditioning speakers using his recently purchased, megabuck integrated amp and matching CD player. He settled on Harbeth speakers, even though he'd never previously heard of them and then I did a 'naughty' - I swopped in my Croft Integrated amp and Rega Saturn CD player. You should have seen his face because these two cost less than his fancy mains leads and incons but were clearly, audibly superior to his expensive electronics.

        Moral of the story is buy wisely and you don't need a small fortune to assemble a system when the speakers are easy to drive, Harbeth.

        {Moderator's comment: but did you investigate *why* the other amp sounded different? It cannot be a circuit design/component issue. It must be a loudness difference which of course is a variable that you couldn't control without measuring equipment. A change in loudness utterly changes human perception of 'quality'. An M40.1 FOC winner is found?}

        Comment


        • #19
          You are welcome here ....

          Originally posted by hifi_dave View Post

          {Moderator's comment: but did you investigate *why* the other amp sounded different? It cannot be a circuit design/component issue. It must be a loudness difference which of course is a variable that you couldn't control without measuring equipment. A change in loudness utterly changes human perception of 'quality'. An M40.1 FOC winner is found?}
          Teaching Granny to suck eggs methinks. I've been listening to Hi-Fi systems for 50 years and selling high quality Hi-Fi for 39 years, so I'm well versed in the art of keeping volume levels the same and to keep everything constant whilst you make a change, one unit at a time.

          In this instance, the amp and CD player were large, very expensive, very powerful and very OTT in the design department and it was these versus simple designs from people who care and listen to everything they make. Differences were clearly audible and if you don't believe, you are all welcome here to do similar comparisons.

          Comment


          • #20
            Science, Not Art

            Originally posted by hifi_dave View Post
            I'm well versed in the art of keeping volume levels the same and to keep everything constant whilst you make a change, one unit at a time. [snip]

            Differences were clearly audible and if you don't believe, you are all welcome here to do similar comparisons.
            But wouldn't Alan and Hug-1 tell us that volume matching must be science, not art: it cannot be done by ear, or else you're using your ear to test your ear, so it must be done electronically. And when the levels are matched in this way, what were {significant} audible differences are no longer audible.

            Bruce

            Comment


            • #21
              You decide - is Alan a liar?

              Originally posted by Euler View Post
              But wouldn't Alan and Hug-1 tell us that volume matching must be science, not art: it cannot be done by ear, or else you're using your ear to test your ear, so it must be done electronically. And when the levels are matched in this way, what were {significant} audible differences are no longer audible.

              Bruce
              Correct. To quote from this post earlier

              3) As there are no standards for the gain (loudness) of amplifiers at the loudspeakers relating to the marking of the volume control knob on the front panel, you cannot be sure how many volts any amp is producing for any volume control position on the front panel. For example, amp A at volume setting 8 produces 18w output; amplifier B produces 41w at volume setting 8 and amp C, which doesn't have a volume control, produces 110w from a fully driven input stage. It is impossible to compare the sound of these without reducing (in this example) amp B to volume setting 3 (to match A's 18w output) and measuring the output of amp C. Who would think to do that?

              Can amplifiers be level matched by ear? Absolutely not! That's why this debate will not die. The failure of the ear as a precision instrument is the source of the problem! You can't use your ear to validate your ear!
              Either Alan has the weight of one hundred years of acoustic research on his side or he is a liar or mad. Simple as that.

              There is not one scrap of evidence in 100 years of acoustic study that the ear can detect and eliminate loudness differences to the necessary precision to allow accurate comparison of randomly selected amplifiers (or CD players or speakers). Can you find contrary evidence in any scientific journals?

              Comment


              • #22
                Let's set up a demo

                Originally posted by HUG-1 View Post
                Correct. To quote from this post earlier

                Either Alan has the weight of one hundred years of acoustic research on his side or he is a liar or mad. Simple as that.

                There is not one scrap of evidence in 100 years of acoustic study that the ear can detect and eliminate loudness differences to the necessary precision to allow accurate comparison of randomly selected amplifiers (or CD players or speakers). Can you find contrary evidence in any scientific journals?
                I repeat - you are welcome here to make comparisons yourself as I have done countless thosands of times in my chosen career of selling quality Hi-Fi for the past 39 years. I assure you that differences are audible. You might think the differences are small and/or not worth paying for but differences there assuredly are.

                Comment


                • #23
                  A deal is struck?

                  The deal is already on the table. You come to us with your amps and your CDs. We measure the amps with precision test equipment and set them to exactly the same gain (loudness) within 0.1dB. We will also check the technical specifications including frequency response. Then we connect the A-B instantaneous switchover box. Then you play music and you switch-over 100 times as you wish. The switch-over is operated by a foot switch. Law of average says 50 times you select A and 50 times B as best sound*. If you can do better than that on just 100 switch over (perhaps 60 right guesses) you win yourself a pair of Monitor 40.1s.

                  If we are wrong about this, the least we can do is put our money where our mouth is and you would have done the whole HUG a great service. Do beware though: in every test like this over the years reported in the hifi press the result is that nobody can hear a difference under these conditions.

                  Deal?

                  * Depending upon the amps you may hear a tiny click when they switch or you may not. If you do not hear this click, you will not know that you have switched-over except the switch-box LED confiming relay change-over. No sonic difference upon switching over. But there is a big sonic difference is the levels are not matched exactly.

                  Comment


                  • #24
                    Check the odds ....

                    Originally posted by HUG-1 View Post
                    Law of average says 50 times you select A and 50 times B as best sound*. If you can do better than that on just 100 switch over (perhaps 60 right guesses) you win yourself a pair of Monitor 40.1s.
                    Ooooh, be careful. I'm no statistician, but I know that even if the results are pure chance, tending to 50/50 over time and given a large enough number, it's entirely possible that within any given sequence there will be less than a perfect 50/50 distribution of results. The larger the number the more likely it is to have an even distribution, but I'd be concerned that 60 out of a 100 may still be within the realm of statistic possibility as an outcome attainable by pure chance alone.

                    I'd suggest you check with your local mathematician before offering odds.

                    Comment


                    • #25
                      Links

                      Originally posted by HUG-1 View Post
                      ...in every test like this over the years reported in the hifi press the result is that nobody can hear a difference under these conditions.
                      Would you please give the link we can read those previous reports?

                      {Moderator's comment: they are already here somewhere. Can anyone help please?}

                      Comment


                      • #26
                        Blind testing

                        Originally posted by A. E. View Post
                        Would you please give the link we can read those previous reports?...
                        Sure. This amplifier sonics issue is not new, and that's one reason it's so frustrating because it has burrowed deep under the skin of an entire generation of hi-fi enthusiasts. A good start would be the Moir paper attached. Also, I think it would be worth reading the tribute to the late James Moir and asking oneself if there are contemporary audio designers who are likely to have his breadth of experience not just of hi-fi but of wider engineering.

                        When we talk of 'blind testing' we mean preventing the listener from actually seeing what he is critiquing: he must judge solely by what his ears tell him and not his eyes. In this regard, the welcoming warm glow of a tube amp versus the antiseptic greyness if a sold state amplifier would obviously bias a listener's observations. Every effort should be taken to judge audio equipment without looking at it: a blindfold is the optimum solution.

                        However, and there are those who are extremely hostile to the concept of blind testing. For example, here in The Absolute Sound's article The blind (mis)-leading the blind
                        you will read that when blind tests do not expose fabled differences between equipments, the test itself is dismissed. This is very odd to me. To quote from the above article ...

                        The latest in this long history is a double-blind test that, the authors conclude, demonstrates that 44.1kHz/16-bit digital audio is indistinguishable from high-resolution digital. Note the word “indistinguishable.” The authors aren’t saying that high-res digital might sound a little different from Red Book CD but is no better. Or that high-res digital is only slightly better and not worth the additional cost. Rather, they reached the rather startling conclusion that CD-quality audio sounds exactly the same as 96kHz/24-bit PCM and DSD, the encoding scheme used in SACD. That is, under double-blind test conditions, 60 expert listeners over 554 trials couldn’t hear any differences between CD, SACD, and 96/24. The study was published in the September, 2007 Journal of the Audio Engineering Society.
                        The AES is the world's professional audio body. Also:
                        .... The answer is that blind listening tests fundamentally distort the listening process and are worthless in determining the audibility of a certain phenomenon.
                        This may be true but it is not valid to dismiss blind listening any more than it is to dismiss clinical trials of drugs which use placebo controls: yes, bias errors can creep in but by and large, a control is an essential tool; and blind listening trials are just another form of control.

                        I have never met an amplifier designer who has invested the necessary $20 and a few hours to make a relay change-over box. Such a simple device would allow the instantaneous change-over from amplifier A driving the speakers to amplifier B, using a hand held or foot operated switch. I prefer the foot switch because I don't want to hear the click of the switch in my hand. Yet, despite the absence of this most basic equipment, enormously inflated claims about sonic superiority are made about one brand of amplifier over another. The claims simply cannot stand up. First, it's unlikely that amp companies acquire products from their competitors (due to high cost) and secondly, even if they did, without the change-over comparator and careful setting of levels, they have no means of arriving at a valid sonic conclusion. So would any claims about sonic superiority be any more or less valid than those used to sell fancy make-up to middle aged women using pseudo-science? What marketing people call 'puff'.

                        Incidentally, it occurs to me that maybe you've never been presented with a foot (or hand) switch driving a change-over comparator. So I wonder if you can imaging what you experience when you press the switch and a tiny fraction of a second later (less than a blink of the eye) the speaker is being driven from the other amplifier. I've tried this a few times over the years and I'd like to share my experience with you ....
                        1. Is there a gap in the music between A and B switch-over? Yes but barely detectable - the room is still singing which masks the gap ...
                        2. How can I be sure that amplifiers are equally loud? The amp levels are closely matched using instruments before the test starts
                        3. At the instant of switch over, will I experience a 'night and day' sonic sensation changing from one amp to another? Most probably you will have to look at the LED light on the change-over box to prove to yourself that you have actually switched over to the other amp
                        4. Are you saying that the switch-over will be sonically seamless? That's been my experience. Some amps produce a tiny audible click at the speaker as the relays change
                        5. That cannot be true. When I hear these amps at home under normal conditions there is a huge difference in sound: black and white. You are seeing the amps, their levels are not matched and you are not switching over in a blink
                        6. I don't believe you. That is counter-intuitive to a lifetime of listening to amps. I'm really very sorry to disappoint you but this has been known for over thirty years and occasionally re-evaluated.


                        >
                        Attached Files
                        Alan A. Shaw
                        Designer, owner
                        Harbeth Audio UK

                        Comment


                        • #27
                          Listening for a difference

                          Please, read my post #24

                          http://www.harbeth.co.uk/usergroup/s...r-©-Alan/page2

                          Using a single player at a time, levels matched using our ears at first, and then by a test-tone cd and a db meter. All the times, no one could hear a difference, or identify the one amp or the other... NO ONE.

                          Comment


                          • #28
                            Restating what we believe ....

                            Just to be clear about this amp comparison subject as I've heard that some other forums seem to have misunderstood our intentions ....

                            1) We definitely, 100% do believe that people (including me) can, do and will hear differences between amplifiers randomly put in front of us, hooked up, switched on and turned up!

                            2) We have observed that for psychoacoustic reasons that we do not understand or pretend to understand, when those very same amps are level matched (with test equipment) and then connected to a good quality relay change-over driving one pair of speaker, that when the change-over is operated entirely at random, those big initial differences heard in 1) diminish to little or nothing. So much so that it's actually not possible (in many instances) to hear any discontinuity or change in the music at all, except the minute gap as the relays flick over - perhaps one thousandth of a second. Even that may not be audible. Surprising, yes it is to me as well. This is, I agree, counter-intuitive.

                            3) We send all those that make amplifiers our good wishes. If the test revealed - and it would be worth a pair of M40.1s - that one amplifier was of such easily demonstrable sonic superiority to all other contenders (I'd buy it immediately) it would truly be a match for our RADIAL cone technology. The entire hi-fi industry would have taken a genuine leap forward and a golden nugget revealed which we'd all do very well to buy. I look forward to that revelation. That designer, that company deserve to be hugely successful.

                            The way things currently stand, every hifi amplifier designer is claiming that his amp 'sounds the best'. That means that if there really is a golden amplifier amongst the pack, we are missing it due to the marketing clamour surrounding all the other amplifiers. They cannot all 'be the best' can they.

                            That's our sole point. We wish we understood the human ear better. Exactly why this switch over test 'levels' what are initially significant performance differences is a mystery. Pass this on.

                            P.S. Link to switch-over box design is here.
                            P.P.S. As a point of clarification, I never listen to more than a few seconds of music before switching over: listening to an entire track is unthinkable. See the next post ... #44
                            Alan A. Shaw
                            Designer, owner
                            Harbeth Audio UK

                            Comment


                            • #29
                              Tidying up the server just now, I found a PDF containing a video from a few years ago. I'd forgotten that I made this at the previous listening room and I could film this in much better quality now. Apologies for the picture/sound quality.

                              The way I work is all about instantaneous change-over. I do not trust my own audio memory. This video shows the foot switch in operation (the actual switch-over box is under the speaker stand). It allows me to compare two speakers instantaneously against each other - an M40 v. an M40.1 - then comparing one with a SHL5, and finally one with the M30. No need to move from the hot spot. No need to listen to the same full track (boring, soporific, teaches you nothing - listening at this time is not for pleasure). Just click-click and change over. You may just about be able to hear the difference in sound picked-up by the camera's inbuilt microphone.

                              So, when comparing amplifiers you use the switch box in reverse: two stereo amplifiers drive one pair of speakers and can can be switched-over to just as fast as you can hear the speakers change over. Completely foolproof. Totally eliminates memory, and most important, emotion, fatigue and attention drift.

                              NOTE: I can guarantee that this PDF is fully Adobe compliant (see footnote) and it will open and play the video in the genuine original Adobe Reader X - free here. The clone PDF readers will not play the video content.

                              >
                              Attached Files
                              Alan A. Shaw
                              Designer, owner
                              Harbeth Audio UK

                              Comment


                              • #30
                                Interesting challenge

                                The challenge Alan has raised is very interesting indeed. I will follow with great interest. May I suggest this discussion be separated into its own thread?

                                Also, an alternative switch for the test may be found here: http://www.dodocus.de/highend.htm

                                Br,
                                Teme

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